Gastrointestinal bleeding in a patient with a continuous-flow biventricular assist device

"Heyde's enigma" in a patient with congenital annular aortic stenosis and its therapeutic challenges

Heyde's syndrome is described as angio-dysplastic gastrointestinal (GI) bleeding in elderly patients with degenerative severe calcific aortic stenosis (AS), resulting in anaemia. It was first reported by Edward C. Heyde in 1958 and thus carried his name. Although this condition is considered to develop in 10-20% of severe AS, it is a less familiar entity in clinical practice. With the rising geriatric population in the communities, there is a proportionate increase in the incidence of AS and accompanying Heyde's syndrome. Heyde's syndrome has also been associated with hypertrophic cardiomyopathy, left ventricular assist device, ventricular septal defect, and patent ductus arteriosus. This article reports a case of Heyde's syndrome associated with congenital annular AS, successfully treated by aortic root enlargement and valve replacement.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12055-023-01636-y.

Flow assessment as a function of pump timing of tubular pulsatile pump for use as a ventricular assist device in a left heart simulator

INTRODUCTION

Although mechanical circulatory support saved many lives during the last decade, clinical observations have shown that the continuous flow pumps are associated with a much higher incidence of gastrointestinal bleeding and kidney problems, among others, compared with the earlier generation pulsatile pumps. However, the presence of several moving mechanical components made pulsatile pumps less durable, bulky, and prone to malfunction, ultimately leading to bias in favor of continuous flow designs.

OBJECTIVE

The aim of the current work is to create a prototype tubular pulsatile pump and to test the timing of the pump in a left heart simulator.

METHODS

A left heart simulator to mimic pumping from a failing heart was created. This was used to experimentally test the output of a prototype ventricular assist device relative to a failing heart in the form of flow and pressure. The effect of pulsation timing was quantified.

RESULTS

A failing heart was simulated with an average flow rate of 1.1 L/min and a systolic pressure of 47 mmHg. With the pump, the flow rate increases to 4.8 L/min and a systolic pressure of 110mmHg, in a copulsation mode, while activating for 300-400 ms. If the activation time is reduced, or increased, the pump becomes less effective. Load on the heart is reduced when the pump operates in a counterpulsation mode.

CONCLUSION

A pulsatile pump, like the one proposed, provides adequate output for mechanical circulatory support, while minimizing the number of moving parts that could otherwise lead to tribological wear.